Along with the continuous development of science and technology, communication positioning technology has also rapidly developed, in particular, UWB (Ultra Wideband) carrier free communications technology. In the early stages, UWB was applied to high-speed data transmission at close ranges. In recent years, sub-nanosecond ultra-narrow pulse is being applied to close-range precision positioning.
Advantages of UWB positioning include high precision, a small size, and low power consumption etc., having the potential for broad applications. In particular, for an ideal situation, a high positioning precision may be acquired, using PDOA (Phase Difference of Arrival), when the positioning algorithm of an arrival angle of a signal is used to determine positioning. When using the PDOA method for positioning, the system is divided into two parts, one part is called an anchor node (Anchor), and the other part is called a beacon (Tag). The beacon transmits a set of time stamped packets, and when received by the anchor node, in accordance with the time stamped information, the distance corresponding therebetween is calculated. At the same time, the anchor node has two sets of receiver chips and antennas, wherein the anchor node can calculate the azimuth (angle) of the beacon by analyzing the phase difference of the signals received by the two sets of receiver chips.
However, there is a problem when PDOA is used to determine the direction and distance of the beacon. As shown in FIG. 1, when the tag is located near the front center of the two antennas of the anchor, measurement precision is high. However, when the tag is located toward the two sides or back, measurement precision is low. Thus, there exists a current technical problem for UWB, wherein when signals arrive from angles for positioning, within some ranges, measurement precision is low.